This invention is in the field of slip seals used in plug valves found in oil and gas applications.
A plug valve has two slips which are pressed against the inside diameter bore of the valve body by the downward motion of the wedge-shaped plug during valve closing (see FIG. 1). This downward motion causes the slip seals bonded to the slips to move outward toward the valve body, thereby producing a seal that holds the pressure of the medium flowing into and through the valve body.
Prior art slip seal profiles have a single point of contact between the slip seal and the valve body (see e.g. FIG. 2). This single point of contact is flat, located in the center of the seal profile, runs the entire length of the slip seal, and provides a relatively wide contact area. Sometimes this contact area does not provide enough resistance to the working pressure of the medium and the slip seal leaks.